As wireless networks evolve and grow in complexity, there are ongoing challenges associated with reaching targeted coverage levels. Recently, in an effort to boost coverage and enhance throughput in wireless networks, network operators have proposed deployment of wireless devices capable of transmitting at a maximum allowable transmit power that is higher than a current maximum allowable transmit power of off-the-shelf wireless devices and/or other currently deployed low power wireless devices. As shown in Table 1 below, the maximum allowable transmit power for wireless devices can be defined by the power class of the wireless device.
TABLE 1Power Class 1Power Class 2Power Class 3Power Class 4Wireless DeviceWireless DeviceWireless DeviceWireless DeviceOperatingPowerTol.PowerTol.PowerTol.PowerTol.Band(dBm)(dB)(dBm)(dB)(dBm)(dB)(dBm)(dB)Band I31±226±223±221±2Band II——26±223±221±2Band III————23±221±2
For example, the maximum allowable transmit power level and tolerance (i.e., power error limits) with which wireless devices can transmit data on a given frequency band or sub-band (e.g., bands I-III) can be specified based on a pre-defined power class (e.g., power classes 1-4 illustrated in Table 1) of the wireless device rather than a physical maximum transmit capability of the wireless device. Off-the-shelf and/or other low-power wireless devices are currently defined in LTE as power class 3 and/or power class 4 wireless devices. Power class 3 and/or power class 4 low-power wireless devices can be configured with a maximum allowable transmit power level of +23 dBm for frequency bands I-III with a nominal power tolerance of ±2 dB (e.g., for E-UTRA bands). High-power class wireless devices are currently defined as power class 1 or power class 2 wireless devices. Power class 1 and/or power class 2 high-power class wireless devices can be configured with a maximum allowable transmit power level of +26 dBm for frequency bands I-II with a nominal power tolerance ±2 dB (e.g., for E-UTRA bands), as illustrated in Table 1.
Because high-power class wireless devices are capable of transmitting at a maximum allowable transmit power that is higher than lower-power class wireless devices, there are potential uplink (UL) interference concerns when high-power class wireless devices are deployed in areas having an access node density designed for low-power wireless devices. Namely, power mismatches between high-power class wireless devices and low-power wireless devices may degrade UL system performance. For example, while deployment of high-power class wireless devices within a radio range of ANs designed for low-power wireless devices enhances throughput of high-power class wireless devices, it degrades the UL link budget for low-power wireless devices operating within the same radio range due, in part, to overlooked power differences between high-power class wireless devices and the low-power wireless devices.
Overview
Exemplary embodiments described herein include systems, methods, and processing nodes for controlling an uplink transmission power of wireless devices on a wireless network. Controlling the uplink transmission power includes dynamically activating and deactivating a high-power transmission mode or changing a power class of the wireless devices in response to changes in a network topology, such as presence or absence of different types of access nodes, and signal level measurements of reference signals transmitted from said different types of access nodes. Such dynamic control of the uplink transmission power in real time minimizes interference that may potentially be caused to uplink transmissions of other wireless devices in the network, and mitigates unnecessary power consumption for wireless devices capable of utilizing the high-power mode.
An exemplary method for controlling a transmit power of a wireless device includes determining that a first signal level of a neighboring access node as measured by a wireless device attached to a serving access node meets a first signal level threshold, and disabling a high-power transmission mode of the wireless device. The high-power transmission mode enables the wireless device to transmit uplink data using a transmission power that is higher than a standard transmission power.
An exemplary system for controlling transmit power of a wireless device includes a first access node having a first coverage area, a second access node having a second coverage area that overlaps with the first coverage area, and a processing node communicatively coupled to the first access node. The processing node is configured to perform operations including receiving a first plurality of measurement reports performed by a corresponding plurality of wireless devices attached to the first access node, each of the first plurality of measurement reports indicating that a first signal level of the first access node meets a first signal level threshold. In response to receiving the first plurality of measurement reports, the processing node instructs each of the plurality of wireless devices to perform measurements of a second signal level of the second access node, receives a second plurality of measurement reports from a subset of the plurality of wireless devices, each of the second plurality of measurement reports indicating that the second signal level meets a second signal level threshold, determines that a number of wireless devices in the subset meets a threshold number of wireless devices, and switches an uplink power class of each of the plurality of wireless devices from a high uplink power class to a low uplink power class.
An exemplary wireless device for controlling a transmit power comprises a memory, a processor, and a transceiver, wherein the memory stores instructions that are executed by the processor to enable the wireless device to perform operations including receiving, from a serving access node, an identifier of the serving access node, wherein the identifier indicates that the serving access node is associated with a small-cell access node, and configuring the transceiver to switch from operating in a high-power transmission mode to operating in a standard-power transmission mode.